Benefits
Well-Absorbed Chelated Form
In a single-dose crossover study of 12 healthy women, 15 mg of zinc as bisglycinate raised serum zinc 43.4% more than the same dose as zinc gluconate, and in a six-week study of 30 young women taking 60 mg a day (above the upper limit), plasma zinc rose with glycinate but not significantly with gluconate. Neither measured absorption with tracers. A 2024 review funded by Pharmavite concluded that glycinate and gluconate are both better absorbed than other forms, while cautioning that the studies were few and small.
Tolerability (Untested Claim)
Bisglycinate is widely marketed as gentler on the stomach. We found no trial comparing its side effects with gluconate, citrate or picolinate in adults; the only randomized comparison of side effects between zinc forms we found, in preschoolers given fortified milk, found no significant difference between an amino acid chelate and zinc sulfate. Taking zinc with a meal and keeping the dose moderate are simpler ways to limit nausea.
Immune Support
Zinc supports T-cell function, NK cell activity, and inflammatory cytokine balance. Adequate zinc status critical for proper immune response.
Skin and Wound Healing (General Zinc Role)
Zinc has a general role in skin integrity and wound healing, and correcting zinc deficiency helps these processes. No trial has tested zinc bisglycinate specifically for a skin or wound-healing outcome.
Reproductive Health
Zinc is critical for sperm production, ovulation, and reproductive hormone regulation. Zinc deficiency contributes to infertility; supplementation in deficient populations supports reproductive function.
Mechanism of action
Chelate Stability and Absorption
Zinc is bonded to two glycine molecules, forming ring structures. It may be taken up partly as an intact complex in addition to the usual zinc transporters (ZIP family); this is not well established in people.
Reduced Absorption Inhibition (Lab Evidence)
Phytates in grains and legumes reduce zinc absorption. Lab studies suggest chelated zinc is less affected by phytate, but this has not been shown in people.
Glycine Synergy (Theoretical)
Glycine itself supports collagen synthesis and immune function. Some theoretical synergy proposed though clinical evidence specific to glycine contribution is limited.
Standard Zinc Functions
All zinc forms share same fundamental biology: cofactor for >300 enzymes, zinc finger transcription factors, immune function, antioxidant via Cu/Zn-SOD.
Clinical trials
Randomized crossover study comparing zinc bisglycinate (15 mg elemental) vs zinc gluconate (15 mg elemental) for serum zinc pharmacokinetics; single-dose crossover.
12 healthy female volunteers, single-dose crossover.
Zinc bisglycinate produced significantly higher serum zinc Cmax and AUC than gluconate, a 43.4% increase. This is a single small study (n=12) measuring blood zinc, a pharmacokinetic surrogate, not a clinical outcome.
Evidence review comparing absorption and bioavailability of zinc acetate, citrate, glycinate, gluconate, oxide, picolinate, sulfate in human studies.
Not a single study; narrative review of human zinc pharmacokinetic studies (Devarshi et al. 2024, Pharmavite-funded).
The authors, Pharmavite employees and an intern, concluded that glycinate and gluconate absorb best, while cautioning that the studies were few and small. Oxide was lowest as a fasting pill but matched zinc sulfate in fortified foods. Picolinate was not consistently superior.